LTC2446

The LTC2446/LTC2447 4-terminal switching enables multiplexed ratiometric measurements. Four sets of selectable differential inputs coupled with four sets of differential reference inputs allow multiple RTDs, bridges and other sensors to be digitized by a single converter. A fifth differential reference input can be selected for any input channel not requiring ratiometric measurements (thermocouples,voltages, current sense, etc.).The flexible input multiplexer allows single-ended or differential inputs coupled with a slaved reference input or a universal reference input.A proprietary delta-sigma architecture results in absolute accuracy (offset, full-scale, linearity) of 15ppm, noise as low as 200nVRMS and speeds as high as 8kHz. Through a simple 4-wire interface, ten speed/resolution combinations can be selected. The first conversion following a speed, resolution, channel change or reference change is valid since there is no settling time between conversions,enabling scan rates of up to 4kHz. Additionally, a 2x mode can be selected for any speed-enabling output rates up to 8kHz with one cycle of latency.

The LTC2446/LTC2447 have some absolute maximum ratings.The supply voltage (VCC) to GND is -0.3V to 6V.The analog input pins voltage to GND is 0.3V to (VCC + 0.3V).The reference input pins voltage to GND is 0.3V to (VCC + 0.3V).The digital input voltage to GND is 0.3V to (VCC + 0.3V).The digital output voltage to GND is 0.3V to (VCC + 0.3V).The operating temperature range LTC2446C/LTC2447C are 0 to 70.The operating temperature range LTC2446I/LTC2447I are -40 to 85.The storage temperature range is 65 to 125.